The present invention relates generally to electronic devices, integrated circuit components and structural mounting frames for assembling such components. More specifically, the present invention relates to creating structural components for these devices that also function for dissipating the heat generated within such devices.
In the small electronics and computer industries, it has been well known to employ various types of electronic component packages and integrated circuit chips, such as the central processing chips employed within cellular telephones and the central processing units (CPU's) used within palmtop computers like the Cassiopeia manufactured by Casio. These integrated circuit chips have a pin grid array (PGA) package and are typically installed into a socket, or are soldered directly onto a computer circuit board. These integrated circuit devices, particularly the CPU microprocessor chips, generate a great deal of heat during operation which must be removed to prevent adverse effects on operation of the system into which the device is installed. For example, the CPU within the Cassiopeia, a microprocessor containing millions of transistors, is highly susceptible to overheating which could destroy the microprocessor device itself or other components proximal to the microprocessor.
In addition to the Cassiopeia microprocessor discussed above, there are many other types of semiconductor device packages that are commonly used in other types of small electronics. Recently, various types of surface mount packages, such as BGA (ball grid array) and LGA (land grid array) type semiconductor packages have become increasingly popular as the semiconductor package of choice for small electronics.
The aforementioned electronic components are commonly employed in electronic devices, such as computers and cellular phones. These devices are being manufactured smaller and smaller and include faster and faster electronic components therein. As a result, heat generation and overheating continues to be a serious concern while the sizes of the devices get smaller. Therefore, problems arise as to how to effectively cool the small electronic components within the small and cramped environments within the device. Typical cooling solutions such as heat sinks and fans are not preferred because they are large and, as a result, consume large spaces within an already cramped electronic device case. In addition, since these small devices, such as cellular phones or laptop computers, must balance competing demands for higher power requirements, smaller battery sizes with the associated power limitations and overall device case size, active cooling solutions, such as powered fans and the like, are not desirable.
These small electronic devices are fabricated by starting with a base structural frame to which all of the integrated circuit devices are attached and over which covers are installed to create the finished product. The traditional solution was to fabricate the structural chassis for these small electronic devices out of a metallic material such as aluminum or magnesium. Although these materials allowed for heat transfer, they are not as lightweight as plastics and are difficult to fabricate into the compact and complex shapes required for the small electronics devices. Often these metallic structural frames require multiple milling operations before they are ready for incorporation into the device.
In addition, electromagnetic interference shielding is often required to ensure proper operation of the electronic device. However, the metallic structural frames provide no shielding and the use of traditional EMI shielding, which typically encase the electronic component within the device to be protected, obstructs proper installation and use of effective solutions for cooling the same electronic component. Therefore, there are competing needs for EMI shielding and effective thermal transfer solutions within electronic devices, particularly in device cases where space is at a premium.
In view of the foregoing, there is a demand for a structural frame for an electronic device that is lightweight, has a low profile and is net-shape moldable from a thermally conductive material so complex geometries for optimal cooling configurations can be achieved. There is also a demand for a structural frame for an electronic device that provides passive heat dissipation for a heat generating electronic component to be cooled. There is further demand for a structural frame for an electronic device that can serve as both a structural frame and a device case. There is still further demand for a structural frame for an electronic device to provide both EMI shielding and superior heat dissipation.